Project Summary The elderly population is rapidly increasing worldwide and those over 60 years old are expected to comprise 20% of the total population by 2050. These demographic changes will focus healthcare needs on those conditions more prevalent in the elderly. Chronic wounds, such as venous leg ulcers, pressure ulcers and diabetic ulcers are over-represented in the elderly population and even now present a significant healthcare burden. These conditions impact approximately 6.5 million patients annually with a cost to the health care system of over $25B. Rarely occurring in the young, the healing of these chronic wounds is confounded by age-related factors such as reduced blood flow, dermal atrophy, increased inflammation and reduced growth factor responses. The high recurrence rate and failure to respond to current therapies indicates the need for improved regenerative therapeutics that can overcome many of the age-associated defects in the wound healing process. Stem cell therapies represent a compelling means of tissue repair and have demonstrated wound healing and soft tissue regeneration in animal models. However, the intuitive concept that therapeutic stem cells engraft and differentiate at sites of tissue damage is not well supported given the low numbers of cells retained over time at application sites in vivo. This suggests that their mechanisms of action occur through paracrine modalities such as secretion of bioactive vesicles, including exosomes. Hence, exploiting stem cell-derived exosomes as a biologic-derived therapy, rather than delivering transient stem cells to treat chronic wounds, is an enticing approach. Secreted extracellular vesicles (EVs), such as exosomes, are packed with potent pro-repair proteins and RNA cargos that are both cell type- specific, as well as, differentially produced and secreted according to the cellular environment. Based on our successful Phase I project, this Phase II program will continue the development and manufacturing of stem cell-derived EVs specifically produced as a chronic wound therapeutic. We will achieve this goal by the following Aims: 1) Optimize the production of selectively-modified hASC EVs for chronic wound healing, 2) In vivo testing of EVs in chronic wound models to establish optimal dosing and route of administration, and 3) Initiate IND enabling studies. This Phase II research program is designed to identify an optimal manufacturing method of bioactive EVs with in vitro and in vivo efficacy and potency, minimal toxicity and strong clinical and translational potential for the treatment of age-related chronic wounds towards a future IND submission. This potential therapeutic has the unique advantage of harnessing the power of stem cells without the need for utilizing complex cell therapies.